In a gas turbine and a steam turbine, maintenance of parts is accomplished regularly or as necessary.
In the maintenance of a blade ring constituting a compressor for the gas turbine and the steam turbine, the upper half section of a turbine housing having a two-piece construction divided into upper and lower sections is removed, and then the blade ring is pulled out of the lower half section of the turbine housing.
As a specific method for pulling out the blade ring, for example, a method described below is used.
As disclosed in Patent Document 1, the blade ring is made of a two-piece construction divided into upper and lower sections. After the upper half section of a turbine housing has been removed, the upper half section of the blade ring is pulled out. Next, to the lower half section of the blade ring left in the turbine housing, a dummy blade ring is mounted in place of the upper half section of the blade ring. Then, the lower half section of the blade ring and the dummy blade ring are turned round through 180 degrees around the axis. In this state, since the lower half section of the blade ring is in a state of being exposed above from the lower half section of the turbine housing, the lower half section of the blade ring is pulled out.    Patent Document 1: Japanese Patent No. 3777440